Commercial porters of eastern Nepal: Health status, physical work capacity, and energy expenditure

Abstract

The purpose of the study was to compare full-time hill porters in eastern Nepal with part-time casual porters engaged primarily in subsistence farming. The 50 porters selected for this study in Kenja (elevation 1,664 m) were young adult males of Tibeto-Nepali origin. Following standardized interviews, anthropometry, and routine physical examinations, the porters were tested in a field laboratory for physiological parameters associated with aerobic performance. Exercise testing, using a step test and indirect calorimetry, included a submaximal assessment of economy and a maximal-effort graded exercise test. Energy expenditure was measured in the field during actual tumpline load carriage. No statistically significant differences were found between full-time and part-time porters with respect to age, anthropometric characteristics, health, nutritional status, or aerobic power. Mean VO2 peak was 2.38 +/- 0.27 L/min (47.1 +/- 5.3 ml/kg/min). Load-carrying economy did not differ significantly between porter groups. The relationship between VO2 and load was linear over the range of 10-30 kg with a slope of 9 +/- 4 ml O2/min per kg of load. During the field test of actual work performance, porters expended, on average, 348 +/- 68 kcal/hr in carrying loads on the level and 408 +/- 60 kcal/hr in carrying loads uphill. Most porters stopped every 2 min, on average, to rest their loads briefly on T-headed resting sticks (tokmas). The technique of self-paced, intermittent exercise together with the modest increase in energy demands for carrying increasingly heavier loads allows these individuals to regulate work intensity and carry extremely heavy loads without creating persistent medical problems.

No ‘free ride’ for African women: A comparison of head-loading versus back-loading among Xhosa women

“…2 More recently, when considering load carriage by Nepalese porters, who use the head-strap method, contrasting conclusions with regard to economy have been made. 21,22 The study, which investigated economy in 26 porters, reported a linear increase in energy expenditure with load and concluded that greater economy was not a factor in explaining the extraordinary load-carrying feats of the porters. 21 In contrast, a 20% greater economy for the porters when compared to experienced mountaineers was reported, 22 albeit based on small numbers of participants (n = 3-10) and it was suggested that this could explain some, if not all, of the advantage porters seem to have in carrying heavy loads.…”

“…21,22 The study, which investigated economy in 26 porters, reported a linear increase in energy expenditure with load and concluded that greater economy was not a factor in explaining the extraordinary load-carrying feats of the porters. 21 In contrast, a 20% greater economy for the porters when compared to experienced mountaineers was reported, 22 albeit based on small numbers of participants (n = 3-10) and it was suggested that this could explain some, if not all, of the advantage porters seem to have in carrying heavy loads. 22 It is important to note, however, that the 'free ride' remains a hypothesis, based on two early studies, 2,3 which examined relatively small numbers of participants.…”

Issues of work intensity, pace, and sustainability in relation to work context and nutritional status

“…The second study (Malville, 1999;Malville et al, 2001) examined load-carrying for commercial porters in eastern Nepal. Porters carried loads averaging 73 AE 15 kg (146% AE 30% of body mass), on a trail of 95 km with 1,500 m absolute elevation difference and 6,500 m (roughly 21,000 feet) in cumulative elevation gain over the series of uphill and downhill stretches along the trail (Malville, 1999).…”